The objective of this protocol is to use a case-control paradigm to compare the response to an intravenous administration of kisspeptin in individuals with and without post-covid-19 syndrome. The study subjects will receive a single bolus of kisspeptin.

The goal of this study is to see whether kisspeptin, a naturally occurring hormone, can stimulate the release of other reproductive hormones in women with hypothalamic amenorrhea (HA). The investigators are also examining whether kisspeptin can help women release eggs from their ovaries. Kisspeptin will be administered subcutaneously (SC) for two weeks in a pulsatile fashion. Ultrasound monitoring of ovarian follicular growth and frequent blood sampling (every 10 minutes for up to two hours) will be performed to assess the physiologic response to kisspeptin over time.

The concentration of functional proteins: kisspeptin, ghrelin, zonulin will be measured and compared in women with polycystic ovary syndrome (PCOS) and insulin resistance (IR), in women with PCOS without IR, and in women without PCOS.

The goal of this study is to see whether kisspeptin, a naturally occurring hormone, can stimulate the release of other reproductive hormones in men and women with idiopathic hypogonadotropic hypogonadism (IHH). The investigators are also examining whether kisspeptin can help women release eggs from their ovaries. Kisspeptin will be administered SC for two weeks in a pulsatile fashion. Ultrasound monitoring of ovarian follicular growth (for women) and frequent blood sampling (every 10 minutes for up to 70 minutes) will be performed to assess the physiologic response to kisspeptin over time. Fu…

We want to find out what happens to reproductive hormone levels; Luteinising Hormone (LH), Follicle Stimulating Hormone (FSH), testosterone and oestradiol when kisspeptin is administered to people for a period of 8 days each month, using either placebo (saline) or kisspeptin in doses of 0.1, 0.3 or 1.0 nmol/kg/hour.

We want to find out if kisspeptin is successful in stimulating oocyte maturation when it is used as a 'trigger' injection during IVF therapy for infertility.

The goal of this study is to learn more about how kisspeptin, a naturally occurring hormone, affects women with high levels of prolactin (also called hyperprolactinemia). Subjects in one group will undergo blood sampling every 10 minutes over two 12-hour periods (one 12-hour period without any intervention and one 12-hour period with intravenous (IV) kisspeptin administration). Subjects in the second group will receive subcutaneous (SC) kisspeptin every 90 minutes for eight days.

The goal of this study is to develop novel treatments for patients with a condition called hypogonadotropic hypogonadism (HH) through the use of exogenous kisspeptin.

The goal of this study is to understand how exogenous kisspeptin affects metabolism by evaluating responses to an oral glucose tolerance test

The goal of this study is to learn about the role of kisspeptin in the reproductive system. Kisspeptin is a naturally occurring hormone in humans that causes the release of other hormones, including gonadotropin-releasing hormone (GnRH) in the body.

The investigators are looking for subjects to complete a study on the role of kisspeptin in the reproductive system. Kisspeptin is a naturally occurring hormone in humans that tells the body to produce other reproductive hormones. However, giving someone a continued amount of kisspeptin over a period of time can have the opposite effect and tell the body to, for a short time, stop making hormones needed for reproduction. By giving 24-hour infusions of kisspeptin, the investigators hope to learn more about the role kisspeptin has in the way bodies function normally and the role it has in condit…

The investigators are seeking healthy volunteers and volunteers with reproductive disorders for the study of the role of dynorphin in the reproductive system. Dynorphin is a naturally occurring opioid hormone that is blocked by naloxone. We hypothesize that naloxone, by blocking dynorphin, will stimulate production of gonadotropin-releasing hormone (GnRH) and kisspeptin, two other naturally occurring reproductive hormones.

The specific objective of this study was to investigate the sensitivity of Kisspeptin receptor 1 (KISS1R) by determining the responsiveness of GnRH neuron to kisspeptin administration across the pubertal stages and adult group through measuring plasma LH (luteinizing hormone) and testosterone concentrations.

The goal of this study is to test whether the hormone kisspeptin has the potential to prospectively diagnose adolescents with self-resolving or permanent delayed puberty. Some children with delayed puberty will eventually enter puberty on their own. However, some children with delayed puberty have a permanent condition and require medical treatment to undergo puberty. Right now, there is no reliable diagnostic tool to tell whether a child's delayed puberty will be self-resolving or permanent. The hormone kisspeptin has the potential to prospectively diagnose adolescents with self-resolving or …

The present study was designed to assess the responsiveness of the hypothalamic pituitary gonadal axis to kisspeptin administration with increasing age in men.

Induction of insulin secretion by kisspeptin is observed in mouse, pig, rat, and human islets in vitro and in rats, mice and monkeys in vivo, but its mechanism is not fully clear. The present study was designed to investigate the role of KP-10 on insulin secretion in adult healthy and obese men with insulin resistance. The aim of selection of obese persons for the present study was to investigate the effect of acute KP-10 administration in a metabolically challenged condition where the pancreatic beta cells are already highly activated. The long-term objective of this study was to understand t…

The goal of this study is to see whether kisspeptin, a naturally occurring hormone, can stimulate the release of other reproductive hormones in women with hypothalamic amenorrhea (HA). The investigators are also examining whether kisspeptin can help women release eggs from their ovaries. Kisspeptin will be administered subcutaneously (SC) for two weeks in a pulsatile fashion. Ultrasound monitoring of ovarian follicular growth and frequent blood sampling (every 10 minutes for up to two hours) will be performed to assess the physiologic response to kisspeptin over time.

The goal of this study is to assess response to kisspeptin as well as the baseline patterns of luteinizing hormone (LH) secretion in individuals with polycystic ovarian syndrome (PCOS).

The objective of this protocol is to assess response to kisspeptin and gonadotropin-releasing hormone (GnRH) stimulation testing as well as the baseline patterns of luteinizing hormone (LH) secretion in individuals who carry variants in genes related to infertility.

The goal of this study is to understand how exogenous kisspeptin affects metabolism by evaluating responses to an hyperglycemic clamp

This study utilizes infusions of kisspeptin in healthy women to isolate the impact of kisspeptin on beta-cell responsivity assessed by the mixed meal tolerance test.

Puberty is the process of transition from childhood into adolescence, signaling the readiness of the human body for reproduction. The Hypothalamic-Pituitary Gonadotropin axis plays the primary role in initiating the puberty, where the hypothalamus secrets gonadotropin releasing hormone (GnRH) in a pulsatile manner, which in turn stimulates the release of luteinizing hormone (LH), and follicle stimulating hormone (FSH) from the anterior lobe of the pituitary gland, and in a final step these hormones stimulate the gonads to release their sex hormones (Testosterone and Estradiol) . Chronic illne…