Provocative tests with Kisspeptin-10 and GnRH set the scene for determining social status and environmental impacts on reproductive capacity in male African lions (Panthera leo).
Ludwig. Mike M; Newton. Claire C; Pieters. Ané A; Homer. Natalie Z M NZM; Feng Li. Xiao X; O'Byrne. Kevin T KT; Millar. Robert P RP
Key Findings
- Adult lions showed a ~10‑fold increase in LH after KP-10 injection, similar to the response to GnRH.
- Testosterone and its precursors rose steadily after KP-10 in adults, but did not increase further with GnRH.
- Young lions only had a significant LH rise with GnRH, not with KP-10.
- Glucocorticoid (stress hormone) levels were unchanged by KP-10.
Practical Outcomes
- For biohackers, the data suggest kisspeptin can strongly stimulate LH and testosterone in mature males, echoing findings in humans, but the study is in lions and uses high‑dose IV administration. It’s not ready for self‑experimentation, but it highlights kisspeptin as a potential tool for future human reproductive or performance research.
Summary
In a study on male African lions, giving a short peptide called kisspeptin-10 (KP-10) caused a big jump in the hormone that triggers testosterone (LH) in adult lions, and it also raised testosterone itself. Young lions only responded to the classic hormone GnRH, not KP-10. Stress hormones didn’t change, so KP-10 might be a clean way to check reproductive health and possibly stress exposure in animals.
Abstract
Understanding the hypothalamic factors regulating reproduction facilitates maximising the reproductive success of breeding programmes and in the management and conservation of threatened species, including African lions. To provide insight into the physiology and pathophysiology of the hypothalamic-pituitary-gonadal reproductive axis in lions, we studied the luteinising hormone (LH) and steroid hormone responses to gonadotropin-releasing hormone (GnRH) and its upstream regulator, kisspeptin. Six young (13.3 ± 1.7 months, 56.2 ± 4.3 kg) and four adult (40.2 ± 1.4 months, 174 ± 6 kg) male lions (Ukutula Conservation Centre, South Africa) were used in this study. Lions were immobilised with a combination of medetomidine and ketamine and an intravenous catheter was placed in a jugular, cephalic or medial saphenous vein for blood sampling at 10-min intervals for 220 min. The ten-amino acid kisspeptin which has full intrinsic activity (KP-10, 1 µg/kg) and GnRH (1 µg/kg) were administered intravenously to study their effects on LH and steroid hormone plasma concentrations, measured subsequently by ELISA and liquid chromatography tandem mass spectrometry (LC-MS/MS), respectively. Basal LH levels were similarly low between the age groups, but testosterone and its precursor levels were higher in the adult animals. Adult lions showed a significant LH response to KP-10 (10-fold) and GnRH (11-fold) administration (p < 0.05 and P < 0.001, respectively) whereas in young lions LH increased significantly only in response to GnRH. In adults alone, testosterone and its precursors steadily increased in response to KP-10, with no significant further increase in response to GnRH. Plasma levels of glucocorticoids in response to KP-10 remained unchanged. We suggest that provocative testing of LH and steroid stimulation with kisspeptin provides a new and sensitive tool for determining reproductive status and possibly an index of exposure to stress, environmental insults such as disease, endocrine disruptors and nutritional status. 272 words.
Study Information
pubmed
2022
2022-09-20T00:00:00.000Z
10.1016/j.ygcen.2022.114127
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