The effect of orchidectomy on thyroid C cells and bone histomorphometry in middle-aged rats

Abstract

This study was to evaluate the effect of androgen deficiency on thyroid immunoreactive C-cells and bone structure and function in a male orchidectomized middle-aged rat model. Fifteen-month-old male Wistar rats were divided into orchidectomized (Orx) and the sham-operated control (Sham) group. In the Orx group significant decreases (P < 0.05) were found in the volume of C cells (by 14%), their relative volume density (by 13%) and serum calcitonin concentration (by 54%) compared to the controls. Analyses of trabecular microarchitecture of the proximal tibia metaphysis showed that Orx induced marked decreases of cancellous bone area, trabecular thickness and trabecular number (by 52, 20 and 19% respectively; P < 0.05), whereas trabecular separation was increased by 27% (P < 0.05). In Orx rats, serum osteocalcin concentration was increased by 119% (P < 0.05), while serum calcium and phosphorus were 6 and 14% (P < 0.05) lower, respectively, compared to the levels in the Sham. In addition, urine calcium content was considerably higher (by 129%; P < 0.05) in Orx animals. These findings indicate that the androgen deficiency caused by Orx in middle-aged rats modulated the structure of C cells and diminished secretion of calcitonin. Histomorphometrical and biochemical analyses demonstrated a decrease of cancellous bone mass and increased bone turnover.

Effects of Calcium Administration on Parathyroid Gland, NaPi 2a Cotransporter and PTH1R in an Animal Model of the Andropause / EFEKTI TRETMANA KALCIJUMOM NA PARATIREOIDNU ŽLEZDU, NAPI 2A KOTRANSPORTER I PTH1R U ANIMALNOM MODELU ANDROPAUZE

“…The biochemical findings showed a significant increase in Pi urinary excretion, together with a decrease in serum Ca 2+ and Pi concentrations after Orx, which is consistent with our previous results (17)(18)(19). The observed increase in urine Pi concentration after Orx could be a consequence of the reduced expression of NaPi 2a cotransporter in the epithelial cells of kidney proximal tubules (19).…”

“…Our previous studies have shown that the orchidectomy-induced lack of steroid hormones caused an enhancement in urinary Ca 2+ excretion and decreased serum Ca 2+ and Pi concentrations (17,18), along with an increment in Pi urinary wasting, in middle-aged male rats (19). These chan ges have led to a decrease in the bone tissue compactness (17,18), which increases the risk of bone fragility (9).…”

Daidzein administration positively affects thyroid C cells and bone structure in orchidectomized middle-aged rats

“…It was previously reported that aged orchidectomized (Orx) male rats represent an adequate animal model for simulation of male osteoporosis due to androgen deficiency and subsequent skeletal effects [8]. Namely, many investigations have shown that androgen deficiency after Orx leads to reduction of bone mass in male rats and mice [9][10][11].…”

“…Thus, C cells may also be very important in the pathogenesis of osteoporosis. We have previously reported that androgen deficiency after Orx modulated the structure of thyroid C cells and inhibited the synthesis and release of CT in middle-aged rats [11].…”

Recent progress in histochemistry

“…One of the symptoms of Low testosterone levels result in decreased bone mass. Filipovic et al (2007) have evaluated the eVect of androgen deWciency on thyroid immunoreactive C-cells, and on bone structure and function in the male orchidectomized middle-aged rat model Orx. In the Orx group signiWcant decreases (P < 0.05) were found in the volume of C cells (by 14%), their relative volume density (by 13%) and serum calcitonin concentration (by 54%) compared to the controls.…”