Prior to study enrollment, potential participants completed a detailed electronic medical history questionnaire. Responses requiring additional query were addressed either in-person, via telephone, or video conference. Body size and composition were assessed at Colorado State University using dual energy X-ray absorptiometry (DEXA; Hologic, DiscoveryW, QDR Series, Bedford, MA, USA), and a physician’s digital scale and stadiometer.
The remaining data collection sessions were completed off-campus on six mornings, each separated by 1–2 weeks depending on participant schedules. The time of protocol initiation was kept constant for each participant. Every data collection was preceded by a 12-h fast, 24-h abstention from alcohol and exercise, and 96-h abstention from any products derived from Cannabis sativa L., including CBD and marijuana.
A venous catheter was introduced to an antecubital or dorsal hand vein and blood (~10 mL) was collected for analysis of baseline circulating concentrations of THC, THC-COOH, THC-OH, glucose, and insulin. Immediately following baseline blood collection, participants self-administered one of five edible marijuana products or a marijuana-free control product (described in detail in a subsequent section). Thirty minutes following marijuana (or marijuana-free control) ingestion, participants imbibed a beverage consisting of 75 g of glucose dissolved in 250 mL of water (i.e., an oral glucose tolerance test (OGTT)).
Relative to marijuana ingestion (Time 0), venous blood was sampled for subsequent analysis of circulating concentrations of THC, THC-COOH, and THC-OH at minutes 10, 20, 30, 45, 60, 75, 90, 120, 180, and 240. Blood was immediately transferred into chilled tubes coated with ethylenediaminetetraacetic acid (K3 EDTA) and placed on ice for up to 30 min before isolation of plasma via chilled (4 °C) centrifugation. One milliliter aliquots of plasma were then placed on ice while being transported to the research facility for storage at −80 °C prior to subsequent analysis.
Relative to marijuana ingestion (Time 0), the carbohydrate beverage was imbibed at minute 30. Venous blood was sampled for subsequent analysis of circulating concentrations of glucose at minutes 25 (i.e., post-marijuana but pre-glucose), 35, 40, 45, 50, 60, 75, 90, 105, 120, 135, 150, 180, and 240, and at minutes 25, 45, 75, 105, 135, and 150 for subsequent analysis of plasma insulin concentration. Blood intended for glucose analysis was transferred to chilled tubes containing sodium fluoride (potassium oxalate), and then immediately placed on ice for transport to the research facility where it was evaluated, in duplicate, without delay using an automated analyzer (YSI 2900 STAT Glucose Lactate Analyzer, YSI Inc., Yellow Springs, OH, USA). Blood intended for insulin analysis was processed in an identical manner to the blood used for THC, THC-COOH, and THC-OH analysis. Plasma insulin concentration was determined in triplicate via enzyme-linked immunosorbent assay ((ELISA) Crystal Chem, Inc., Elk Grove Village, IL, USA).
The remaining data collection sessions were completed off-campus on six mornings, each separated by 1–2 weeks depending on participant schedules. The time of protocol initiation was kept constant for each participant. Every data collection was preceded by a 12-h fast, 24-h abstention from alcohol and exercise, and 96-h abstention from any products derived from Cannabis sativa L., including CBD and marijuana.
A venous catheter was introduced to an antecubital or dorsal hand vein and blood (~10 mL) was collected for analysis of baseline circulating concentrations of THC, THC-COOH, THC-OH, glucose, and insulin. Immediately following baseline blood collection, participants self-administered one of five edible marijuana products or a marijuana-free control product (described in detail in a subsequent section). Thirty minutes following marijuana (or marijuana-free control) ingestion, participants imbibed a beverage consisting of 75 g of glucose dissolved in 250 mL of water (i.e., an oral glucose tolerance test (OGTT)).
Relative to marijuana ingestion (Time 0), venous blood was sampled for subsequent analysis of circulating concentrations of THC, THC-COOH, and THC-OH at minutes 10, 20, 30, 45, 60, 75, 90, 120, 180, and 240. Blood was immediately transferred into chilled tubes coated with ethylenediaminetetraacetic acid (K3 EDTA) and placed on ice for up to 30 min before isolation of plasma via chilled (4 °C) centrifugation. One milliliter aliquots of plasma were then placed on ice while being transported to the research facility for storage at −80 °C prior to subsequent analysis.
Relative to marijuana ingestion (Time 0), the carbohydrate beverage was imbibed at minute 30. Venous blood was sampled for subsequent analysis of circulating concentrations of glucose at minutes 25 (i.e., post-marijuana but pre-glucose), 35, 40, 45, 50, 60, 75, 90, 105, 120, 135, 150, 180, and 240, and at minutes 25, 45, 75, 105, 135, and 150 for subsequent analysis of plasma insulin concentration. Blood intended for glucose analysis was transferred to chilled tubes containing sodium fluoride (potassium oxalate), and then immediately placed on ice for transport to the research facility where it was evaluated, in duplicate, without delay using an automated analyzer (YSI 2900 STAT Glucose Lactate Analyzer, YSI Inc., Yellow Springs, OH, USA). Blood intended for insulin analysis was processed in an identical manner to the blood used for THC, THC-COOH, and THC-OH analysis. Plasma insulin concentration was determined in triplicate via enzyme-linked immunosorbent assay ((ELISA) Crystal Chem, Inc., Elk Grove Village, IL, USA).
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