Castration Effects on the Response of Rat Pituitary Cells to Luteinizing Hormone-Releasing Hormone: Retention in Dispersed Cell Culture*

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Abstract
Dispersed cell cultures are becoming more frequently used for the study of the anterior pituitary response to the physiological secretagogue, LHRH. A systematic comparison of the LHRH-induced LH and FSH release response of dispersed pituitary cells from intact and castrated adult rats of both sexes has thus far not been reported. Sixty-day-old Holtzman rats of both sexes (normal and 1-week castrated) were used as donors for anterior pituitary cell cultures. The cells were dispersed by trypsinization and established in monolayer culture in a medium composed of Dulbecco’s Modified Eagle’s Medium containing fetal calf serum, horse serum, and antibiotics. The cells exhibited high levels of basal gonadotropin release during the first 24 h in culture. By day 3, basal release had diminished to a low and stable level which became undetectable by day 35. Initially, the cells manifested a loss of LHRH response capability which was regained by day 3. Dispersed pituitary cell cultures from normal male rats indicated low basal release of LH and FSH, which remained unaffected by castration. Although pituitary cells from castrated males gave the greater response, cells from both normal and castrated males gave significant LH but not FSH release in response to LHRH. Cells from normal females exhibited higher basal release of LH but not FSH compared to cells from normal or castrated males. Castration in females suppressed LH basal release while increasing FSH basal release. Cells from both normal and castrated females gave significant LH and FSH release in response to LHRH. Compared to normal female cells, castration increased the LHRH release response by more than 2-fold for both LH and FSH and yielded cells which evidenced the highest observed sensitivity to low levels (0–5 ng/ml) of LHRH. All animals models used exhibited a maximum release response (LH and FSH) of 60–80% of the total hormone present. Evidence of LHRH-stimulated increase in total LH in the incubation system was shown by cell cultures of all pituitary cells studied. Although cells from female rats showed greater increases than those from male rats, greater LHRH levels were required for this effect. Increased total FSH was shown only by normal and castrated females. These results suggest that the observed LHRH response of pituitary cell cultures is strongly influenced by the in vivo endocrine condition of the donating animal and that the pituitary cell itself may possess some potential of determining LHRH response. (Endocrinology106: 1706, 1980)