Pituitary folliculostellate cells (FSCs) are thought to partially inhibit pituitary hormone secretion through a paracrine mechanism. In this process, one of the important questions is what factors regulate the function of FSCs. Because ACh is synthesized in and possibly released from the corticotrophs and lactotrophs, we examined whether FSCs respond to ACh by the method of Ca2+ imaging in primary cultured FSCs from male Wistar rats. ACh (30 nM-3 microM) increased intracellular calcium concentration ([Ca2+](i)) of FSCs in a concentration-dependent manner, with an initial rapid rise followed by a relatively sustained increase. The complete block of the response by atropine and pirenzepine suggests involvement of muscarinic receptors. Depletion of the stored Ca2+ by thapsigargin blocked the response completely. Blockers of phospholipase C, U-73122 and neomycin, suppressed significantly the rise of [Ca2+](i). These results suggest that ACh increases [Ca2+](i) in FSCs by activating phospholipase C, presumably through activation of M(1) receptors. The rise in [Ca2+](i) could trigger a variety of Ca2+-dependent cellular processes, including the synthesis and release of bioactive substances, which in turn act on endocrine cells.

The effects of different heating conditions set to prevent food poisoning on the volatile components, lipid oxidation, and odor of yellowtail fish, Seriola quinqueradiata, were investigated. The heating conditions did not affect the lipid oxidation, fatty acid composition, and volatile compounds of each part of the flesh. High-temperature/short-time (90 °C for 6 min) heating led to significantly higher trimethylamine (TMA) contents in all muscle parts and higher odor intensity of TMA in dark muscle (DM) compared to those of lower temperature heating. Sensory evaluation showed that the odor intensities of all muscle parts heated at high-temperature/short-time were stronger than those at low-temperature/long-time (63 °C for 30 min). All DM samples had less odor palatability than the other flesh parts. Therefore, DM may have contributed to the unfavorable odor of steamed yellowtail fish meat and high-temperature/short-time heating may have enhanced the odor of all flesh parts compared with those subjected to low-temperature/long-time.

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