Effects of Long-term Treatment with Caffeine on the Ultrastructure of the Golden Hamster Parathyroid Gland and Tibia

Abstract

Summary: The ultrastructure of the parathyroid gland and the SEM appearances of the tibia were studied in hamsters with and without administration of caffeine. Caffeine was treated orally each day at either 23 mg (low dose) or 10 mg (high dose) per 100 g body weight for a period of 17 or 32 days. Statistical analysis showed no significant differences among all groups examined regarding the serum calcium level. Transmission electron microscopy of the parathyroid gland revealed that the volume densities occupied by the mitochondria, Golgi complexes and rough endoplasmic reticulum of caffeine-treated groups were found significantly higher when compared with controls. The number of secretory granules observed close to the cell membrane per total amount of these granules revealed significant increase in all caffeine-treated animals. The bone mineral content (BMC) values were closely related to body weight. In the high dose caffeine-treated hamsters increment of the mean BMC and body weight values was significantly lower than those of the controls after 32 days. In the scanning electron microscopic studies of the tibia, no alteration in the morphometric parameters was demonstrated.It is considered that the synthesis and release of parathyroid hormone is stimulated following caffeine consumption. Our data suggest that although chronic administration of caffeine in the hamster may slightly increase bone turnover as evidenced by the BMC decrease, bone morphometry was not altered. Thus the osteoporotic changes were not proved in this study.

Caffeine as a Neoadjuvant Therapy in Parathyroid Adenomas: A Narrative Review

“…Accordingly, the parathyroid glands in humans and hamsters are similar in microscopic structure and function [ 17 ]. A study was conducted on 42 adult female hamsters of average body weight (135 gm) to find a correlation between the administration of caffeine and any changes in the function and structure of the parathyroid glands and if that affects the bone metabolism [ 18 ]. The 42 hamsters were divided into two groups (21 hamsters in each) for 17 and 32 days, respectively.…”

“…A second group received 2.5 mg of caffeine dissolved in 0.5 mL water for each 100 gm body weight equivalent to 340 mg/70 kg in human bodies. The third group received 10 mg of caffeine dissolved in 0.5 mL water for each 100 gm body weight equivalent to 1,360 mg of caffeine in a 70 kg person [ 18 ]. All the doses were given orally once daily.…”

“…Serum calcium was measured and transmission electron microscopy of the parathyroid gland was performed on day 18 for the first group and on day 33 for the second one. Bodyweight, mineral content of bone (bone mineral density/body weight), and bone mineral density were measured for all groups on day 0 before the study started and on the last day for each group [ 18 ]. The results showed no significant difference in serum calcium levels for all groups.…”

“…When examined the parathyroid glands, there was a remarkable increase in the number of mitochondria, the surface area of rough endoplasmic reticulum, and the Golgi apparatus in the caffeinated groups, suggesting increased PTH synthesis. Measuring the PTH was not possible in that study [ 18 ]. As regards to body weight and bone mineral density, there was no significant difference for the 17-day group.…”

“…For the 32-day group, despite an increase in both weight and mineral density of bone, it was slower in the caffeinated group than the control, and the mineral content of bone was decreased in the highly caffeinated group. This suggests that caffeine affects body metabolism but not necessarily bone mineral density or content [ 18 ].…”