Effect of progesterone on secretagogue-evoked secretory responses in the isolated pancreas

Abstract

The study investigates the effect of the neurotransmitter acetylcholine (ACh), the gut hormone, cholecystokinin-octapeptide (CCK-8) and the steroid hormone, progesterone on amylase release and preliminary data on ion (potassium (K), sodium
(Nat), magnesium (Mg 2+) and calcium (Ca 2+) transport in the isolated pancreas of both male and female rats. The pattern of distribution of progesterone receptors in both the male and female rat pancreas was also investigated for comparison. The results show that stimulation of the isolated pancreatic segments with different concentrations of either ACh or CCK-8 alone or in combination with progesterone 104 M progesterone resulted in stimulating effects on amylase release.
ACh or CCK-8 alone-elicited marked increases in amylase output in both the male and female pancreas and combining 10 4 M progesterone with either ACh or CCK-8 resulted in marked potentation in amylase release compared with the response
obtained by these alone. Also this potentiation was more prominent in the female pancreas than in the male. This corresponds with the immunohistochemical techniques, which confirmed the presence of progesterone receptors. Moreover, in the female, progesterone receptors were found not only in the nucleus but also on the cell membrane, where as in the male they were only seen in the nucleus.
The results of the study have demonstrated the presence of progesterone receptors in both the male and female rat pancreas and that the steroid hormone has potentiating effects on amylase release. It can be concluded that it is essential to study the effects of different secretagogues on male and female pancreas separately. When the results are combined they show gender-related effects compared to the response obtained in either male or female separately.