Expression of hypothalamic KiSS-1 system and rescue of defective gonadotropic responses by kisspeptin in streptozotocin-induced diabetic male rats.
Castellano. Juan M JM; Navarro. Victor M VM; Fernández-Fernández. Rafael R; Roa. Juan J; Vigo. Eva E; Pineda. Rafael R; Dieguez. Carlos C; Aguilar. Enrique E; Pinilla. Leonor L; Tena-Sempere. Manuel M
Key Findings
- Diabetes sharply lowers hypothalamic KiSS‑1 (kisspeptin) mRNA levels in male rats.
- Acute kisspeptin‑10 injections trigger strong LH and testosterone spikes despite diabetic suppression of the gonadal axis.
- Repeated kisspeptin dosing keeps LH/testosterone elevated and partially rescues prostate and testis size.
- Central leptin infusion, but not insulin, restores KiSS‑1 expression and normal hormone levels.
Practical Outcomes
- For biohackers, this study suggests kisspeptin could be a candidate for boosting reproductive hormones in diabetic or hypogonadal men, but the work is limited to rats and uses brain‑direct delivery. No human dosing, safety, or oral formulations are known yet, so it’s not ready for a DIY protocol. It does, however, highlight the importance of the kisspeptin‑leptin link for hormone regulation, pointing to future research directions.
Summary
In male rats with type 1‑like diabetes, the brain's kisspeptin system is turned down, which leads to low reproductive hormones. Giving kisspeptin restores sudden bursts of luteinizing hormone (LH) and testosterone, and even helps the prostate and testes stay bigger. Leptin (but not insulin) can also bring the kisspeptin system back to normal.
Abstract
Hypogonadotropism is a common feature of uncontrolled diabetes, for which the ultimate mechanism remains to be elucidated. Kisspeptins, ligands of G protein-coupled receptor 54 (GPR54) encoded by the KiSS-1 gene, have recently emerged as major gatekeepers of the gonadotropic axis. Alteration in the hypothalamic KiSS-1 system has been reported in adverse metabolic conditions linked to suppressed gonadotropins, such as undernutrition. However, its potential contribution to defective gonadotropin secretion in diabetes has not been evaluated. We report herein analyses of luteinizing hormone (LH) responses to kisspeptin and hypothalamic expression of the KiSS-1 gene in streptozotocin (STZ)-induced diabetic male rats. In addition, functional studies involving kisspeptin replacement or continuous administration of leptin and insulin to diabetic male rats are presented. Kisspeptin administration evoked robust LH and testosterone bursts and enhanced postgonadectomy LH concentrations, despite prevailing attenuation of gonadotropic axis in diabetic animals. In addition, hypothalamic KiSS-1 mRNA levels were unambiguously decreased in diabetic male rats, and the postorchidectomy rise in KiSS-1 mRNA was severely blunted. Repeated administration of kisspeptin to diabetic rats evoked persistent LH and testosterone responses and partially rescued prostate and testis weights. In addition, central infusion of leptin, but not insulin, was sufficient to normalize hypothalamic KiSS-1 mRNA levels, as well as LH and testosterone concentrations. In summary, we provide evidence for altered expression of the hypothalamic KiSS-1 system in a model of uncontrolled diabetes. This observation, together with the ability of exogenous kisspeptin to rescue defective LH responses in diabetic rats, unravel the physiopathological implication, and potential therapeutic intervention, of the KiSS-1 system in altered gonadotropin secretion of type 1 diabetes.
Study Information
pubmed
2006
2006-09-01T00:00:00.000Z
10.2337/db05-1584
259
45