Effect of neurotensin on pituitary gonadotropin release in vivo

To investigate the effect of a newly purified hypothalamic tridecapeptide, neurotensin on LH and FSH release from the anterior pituitary gland in intact male rats, two different doses of neurotensin (0.2 nmole/animal: high dose, 0.02 nmole/animal: low dose) were injected intravenously into male mature Sprague-Dawley strain rats and blood was collected before and 30 min after the administration. Both doses of neurotensin increased serum LH and FSH levels but the alteration was slight and the values were not statistically significant and less potent to stimulate the anterior pituitary as compared to LH-RF. Neurotensin was suggested to be "kinin" rather than the releasing factor and its biological potency was discussed.